[tracing] Make memory-infra unregristration DCHECK stricter

content/browser/tracing/memory_tracing_browsertest.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <stdint.h>
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/run_loop.h"
 #include "base/thread_task_runner_handle.h"
@@ skipping 56 matching lines @@
   }
 
  protected:
   void SetUp() override {
     callback_call_count_ = 0;
     last_callback_dump_guid_ = 0;
     last_callback_success_ = false;
 
     mock_dump_provider_.reset(new MockDumpProvider());
     MemoryDumpManager::GetInstance()->RegisterDumpProvider(
-        mock_dump_provider_.get(), "MockDumpProvider", nullptr);
+        mock_dump_provider_.get(), "MockDumpProvider",
+        base::ThreadTaskRunnerHandle::Get());
     MemoryDumpManager::GetInstance()
         ->set_dumper_registrations_ignored_for_testing(false);
     ContentBrowserTest::SetUp();
   }
 
   void TearDown() override {
     MemoryDumpManager::GetInstance()->UnregisterDumpProvider(
         mock_dump_provider_.get());
     mock_dump_provider_.reset();
     ContentBrowserTest::TearDown();
@@ skipping 135 matching lines @@
 
   EnableMemoryTracing();
   RequestGlobalDumpAndWait(false /* from_renderer_thread */);
   EXPECT_EQ(1u, callback_call_count_);
   EXPECT_NE(0u, last_callback_dump_guid_);
   EXPECT_TRUE(last_callback_success_);
   DisableTracing();
 }
 
 }  // namespace content